1. Field of the Invention
The present invention relates to an apparatus and method for preparing samples observed on a scanning electron microscope, transmission electron microscope, or other instrument.
2. Description of Related Art
One known apparatus for preparing samples to be observed on a scanning electron microscope (SEM) or transmission electron microscope (TEM) is described, for example, in Japanese Patent No. 3263920. This known apparatus is an ion beam processing system that processes a sample into a shape adapted for SEM or TEM observation by irradiating the sample with an ion beam to etch it.
Furthermore, in the ion beam processing system of Japanese Patent No. 3263920, a shielding material is placed over the sample, and the sample is processed by the ion beam directed at the sample with the boundary defined by an end surface of the shielding material. As a result of this ion beam processing, an electron microscopy sample having a desired cross section is completed.
The sample prepared by the ion beam processing system described above is set on a SEM or TEM. The cross section of the sample produced by the ion etching is irradiated with an electron beam and observed.
If the sample contains a substance M that is not easily etched by the ion beam, as shown in FIG. 1(a), the portion hidden by the substance M is not etched by the ion beam processing system of Japanese Patent No. 3263920, but left behind. As a result, after the etching, the sample assumes a shape, for example, as shown in FIG. 1(b). The unetched portion Sa creates an obstacle in observing the desired cross section Sb by electron microscopy, though the cross section has been produced as a result of considerable effort.